纳米晶镍块体的制备及烧结致密度研究

Preparation and Analysis of Bulk Nanocrystalline Nickel

以高能球磨法和直流氢电弧等离子蒸发法两种不同工艺制备纳米晶镍粉体,并结合预压烧结工艺制备了纳米晶镍块体试样,研究了纳米晶镍块体结构、形貌的变化。运用TEM技术观察了两种粉体的形貌,并给出了选区电子衍射图;运用XRD、Archimedes法等分析手段对纳米晶镍块体的致密度及晶粒尺寸进行测定,并对两种试样进行了对比分析,表征结果显示,随着烧结温度的升高,纳米晶镍块体试样的晶体尺寸增大,晶格应变减小,同时致密度增加;高能球磨试样晶粒生长速率和致密度升高速率比等离子蒸发试样的快。

The nanocrystalline nickel powder were prepared by high-energy ball milling and DC arc plasma evaporation method respectively, subsequently the two kinds of powder were consolidated into bulk nanocrystalline nickel by cold compaction and sintering. The structure and morphology change of the bulk nanocrystalline Nickel were researched. The particles were observed by TEM and the selected area electron diffraction patterns of nickel powders were shown; then XRD and Archimedes method were carried out to determine grain size and porosity of the two specimens respectively and contrastive analysis were performed. The results of investigation showed that, for both specimens, grain size and relative density increased, but lattice strain decreased with the increasing sintering temperature. Moreover, it was found that grain size and relative density growth rate of milling sample were higher than those that prepared by plasma evaporation method.